JP2007177626A - Device for controlling gas turbine load - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for controlling a gas turbine load capable of quickening following of power generator output to change of a demand load setting value even when a time constant of proportional-plus-integral control is set long. <P>SOLUTION: The device 30 includes a load setting means, a first bias setting means, a second bias setting means, a target output setting means and the like, wherein the target output setting means sets target output by adding a plus side bias value to LDSET when a load set value is gradually increased by the load setting means according to increase of the demand load setting value input from a demand load setting means and sets the target output by subtracting a minus side bias value from the LDSET when the load set value is gradually decreased by the load setting means according to decrease of the demand load setting value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas turbine load control device that controls the amount of fuel supplied to a gas turbine so that a gas turbine output (generator output) becomes a target output.

  When the generator is operating in the gas turbine power generation facility, that is, when the generator is connected to the power system (power network) and the power generated by the generator is transmitted to the power system, the gas turbine power generation facility is equipped. It is necessary to control the amount of fuel supplied to the gas turbine so that the generator output (active power) follows the change in the required load setting value of the power system by the gas turbine load control device. The required load setting value is normally sent from the central power supply center to the gas turbine load control device as a required load setting command.

  FIG. 11 is a block diagram showing the configuration of a conventional gas turbine load control device, and FIG. 12 shows LDSET (target output) and generator output (actual output) with respect to an increase in required load set value when the gas turbine load control device is applied. It is explanatory drawing which shows the change of ().

  As shown in FIG. 11, the gas turbine power generation facility has a configuration in which a rotating shaft 4 of a generator 3 is connected to a rotating shaft 2 of a gas turbine 1. Although detailed illustration is omitted, the gas turbine 1 includes a gas turbine body, a compressor, and a combustor. When the gas turbine 1 is activated, the generator 3 is rotated by the gas turbine 1 to generate power. This generated power is transmitted from the generator 3 to the power system via a circuit breaker, a transformer, etc. (not shown). The generated power (active power) at this time is transmitted by the MW converter 5 which is an active wattmeter. It is measured. The measured value (actual output) of the MW converter 5 is fed back to the gas turbine load control device 10.

  In addition, a fuel control valve 6 is connected to the combustor of the gas turbine 1, and gas turbine fuel such as gas or liquid sent from a fuel supply facility such as a fuel tank (not shown) flows at the fuel control valve 6. It is controlled and supplied to the combustor. The gas turbine load control device 10 performs opening / closing control of the fuel control valve 6 (control of the amount of fuel supplied). The gas turbine load control device 10 includes deviation calculators (subtractors) 11 and 15, high / low monitors (comparators) 12 and 13, an analog memory 15, and a PI controller 16.

  In the deviation calculator 11, a deviation (load setting deviation = request) between a required load setting value (command) sent from a central power supply center (high-order computer) (not shown) and LDSET (load setting value) which is an output of the analog memory 14. Load setting value-LDSET) is calculated.

  The high / low monitor 12 determines whether or not the load setting deviation is 0.1 MW or more (load setting deviation ≧ 0.1 MW). If it is determined that the load setting deviation is 0.1 MW or more, the analog memory 14 is checked. Output LDSET increase command. That is, the LDSET increase command is turned ON when the load setting deviation is 0.1 MW or more, and turned OFF when the load setting deviation is smaller than 0.1 MW.

  The high / low monitor 13 determines whether or not the load setting deviation is −0.1 MW or less (load setting deviation ≦ −0.1 MW). If it is determined that the load setting deviation is −0.1 MW or less, the analog memory 14 Output an LDSET decrease command. That is, the LDSET reduction command is turned on when the load setting deviation is −0.1 MW or less, and is turned off when the load setting deviation is larger than −0.1 MW.

  In the analog memory 14, when an LDSET increase command is input from the high / low monitor 12 (when the LDSET increase command is turned ON), an increase in LDSET is started and while the LDSET increase command is continuously input (while the LDSET increase command is ON). Gradually increases LDSET at a predetermined rate of increase (for example, 10 MW / min), and stops the increase in LDSET when no LDSET increase command is input from the high / low monitor 12 (when the LDSET increase command is turned OFF). In addition, when an LDSET decrease command is input from the high / low monitor 13 (when the LDSET decrease command is turned ON), the analog memory 14 starts to decrease the LDSET, and continues to input the LDSET decrease command (when the LDSET decrease command is ON). During the period, LDSET is gradually decreased at a predetermined decrease rate (for example, -10 MW / min), and when the LDSET decrease command is not input from the high / low monitor 13 (when the LDSET decrease command is turned OFF), the decrease in LDSET is stopped. . The LDSET is output from the analog memory 14 to the deviation calculator (subtracter) 15 as a target output.

  The deviation calculator 15 calculates a deviation (output deviation = target output−generator output) between the target output (LDSET) set in the analog memory 14 and the generator output (active power) measured by the MW converter 5. To do.

  The PI controller 16 controls the opening of the fuel control valve 6 by performing a proportional / integral calculation based on the output deviation calculated by the deviation calculator 15. That is, if the target output is larger than the generator output, the output of the gas turbine 1 is increased by increasing the opening of the fuel control valve 6 and increasing the amount of fuel supplied to the gas turbine 1 (combustor). The output of the generator 3 is increased (the generator output is matched with the target output). If the target output is smaller than the generator output, the opening of the fuel control valve 6 is reduced to reduce the amount of fuel supplied to the gas turbine 1 (combustor), thereby reducing the gas turbine output and the generator. Reduce the output (make the generator output match the target output). In the deviation calculator 16, K is a proportional gain, s is a Laplace operator, T is a time constant (integral time constant) of proportional / integral control, and 1 / T is an integral gain.

  For example, as illustrated in FIG. 12, the required load set value, the target output (LDSET), and the generator output (actual output) coincide with each other until time T1, and the required load is set according to a command from the central power supply center at time T1. When the value increases stepwise (in the example shown, from 100 MW to 200 MW), the deviation between the required load setting value calculated by the deviation calculator 11 and LDSET is 0.1 MW or more, so the high / low monitor 12 An LDSET increase command is output to the analog memory 14 (the LDSET increase command is turned ON). As a result, the analog memory 14 causes the LDSET to reach the required load setting value (200 MW) at the time T2 from the time T1 (until the load setting deviation becomes smaller than 0.1 MW and the LDSET increase command is turned OFF). It gradually increases at a predetermined rate of increase. That is, the target output gradually increases at a predetermined increase rate.

  Then, the output deviation between the target output and the generator output (active power) at this time is calculated by the deviation calculator 15, and the proportional / integral calculation is performed by the PI controller 16 based on this output deviation. Based on the result of the integral calculation, the fuel control valve 6 operates (the valve opening of the fuel control valve 6 increases). As a result, the amount of fuel supplied to the gas turbine 1 increases and the gas turbine output increases, so that the generator output (active power) increases, and finally the generator output (active power) is set to the target output (requested). Load setting value).

  Note that the reason why the LDSET (target output) is gradually increased or decreased by using the analog memory 14 is that the LDSET (target output) is set at an allowable change rate of the gas turbine 1 even if the required load setting value is suddenly changed. It is for changing. If LDSET (target output) is also changed suddenly in response to a sudden change in the required load set value, the output of the gas turbine 1 may be suddenly changed to cause damage to the gas turbine 1 or the like.

  As a prior art document related to the present application, there is the following Patent Document 1. Patent Document 1 discloses a load control method and apparatus for a multi-axis combined cycle plant.

Japanese Patent Laid-Open No. 10-196315

  Recently, the power transmission side (power system side) is required to make the generator output follow the change in the required load set value faster from the gas turbine power generation equipment side. For example, in a country where the power generation company and the power transmission company are different, the power transmission company requires the power generation company to quickly follow the generator output with respect to a change in the required load setting value.

  On the other hand, in the conventional gas turbine load control device 10, if the time constant T of proportional / integral control is shortened (that is, if the integral gain 1 / T is increased), the generator output can follow the change in the required load set value. However, if the time constant T of the proportional / integral control is shortened, the gas turbine load control device 10 generates power in response to fluctuations in the generator output (active power) accompanying fluctuations in the power factor of the power system. In order to keep the machine output (active power) constant, the increase and decrease in the amount of fuel supplied to the gas turbine 1 are repeated more frequently. This is not preferable for the gas turbine 1.

  For this reason, it is necessary to set the time constant T of proportional / integral control to be long so that the amount of fuel supplied to the gas turbine 1 is stabilized. If the time constant T of proportional / integral control is set to be long, the required load set value is set. Since the follow-up of the generator output at the time of the change of time becomes slow, it is not possible to satisfy the demand for improvement in follow-up from the power system side (transmission company side).

  Therefore, in view of the above circumstances, the present invention is a gas turbine load capable of speeding up the follow-up of the generator output (active power) to the change in the required load setting value even if the time constant of the proportional / integral control is set to be long. It is an object to provide a control device.

The gas turbine load control device according to the first aspect of the present invention for solving the above-mentioned problem is to gradually increase the load set value at a predetermined increase rate until the required load set value is reached when the required load set value increases, Load setting means for gradually decreasing the load set value at a predetermined decrease rate until the required load set value is reached when the set value decreases;
First bias setting means for setting a positive bias value as a bias value for the load setting value;
Second bias setting means for setting a negative side bias value as a bias value for the load setting value;
When the load setting value is gradually increased by the load setting means in response to the increase in the required load setting value, the target output of the generator is obtained by adding the plus side bias value to the load setting value. When the load setting value is gradually decreased by the load setting means in accordance with a decrease in the required load setting value, the target output is obtained by subtracting the negative side bias value from the load setting value. Target output setting means for setting
Output deviation calculating means for calculating an output deviation between the target output and the generator output measured by the generator output measuring means;
Proportional / integral control means for controlling the flow rate control means for the fuel of the gas turbine that rotationally drives the generator by performing proportional / integral calculation based on the output deviation.

Further, the gas turbine load control device of the second invention is the gas turbine load control device of the first invention.
In the first bias setting means, the positive side bias value is a function of the load setting value,
The second bias setting means is characterized in that the minus side bias value is a function of the load setting value.

Moreover, the gas turbine load control device of the third invention is the gas turbine load control device of the first or second invention.
In the first bias setting means, the positive bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when the load setting means starts to increase the load setting value, And, when the load setting means ends the increase of the load set value, the load set means decreases the predetermined value from the predetermined value until it gradually becomes zero,
In the second bias setting means, the positive bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when the load setting means starts to decrease the load setting value, In addition, when the load setting means finishes reducing the load set value, the load set means reduces the load set value from the predetermined value to zero gradually at a predetermined decrease rate.

  According to the gas turbine load control device of the first aspect of the invention, the target output setting means does not use the load set value as it is as the target output of the generator, but loads the load setting means according to the increase in the required load set value. When the set value is gradually increased, the target output of the generator is set by adding the positive bias value to the load set value, and the load set value is set by the load setting means according to the decrease in the required load set value. For example, to operate the gas turbine stably against power factor fluctuations in the power system to set the target output of the generator by subtracting the negative bias value from the load setting value. Even if the time constant of proportional / integral control is set so as to be longer, the follow-up of the generator output can be made faster with respect to the increase or decrease of the required load set value.

  According to the gas turbine load control device of the second aspect of the invention, the first bias setting means uses the plus side bias value as a function of the load setting value, and the second bias setting means uses the minus side bias value as the load setting value. Since it is a function, the plus side bias value and the minus side bias value can be set to more appropriate values according to the gas turbine load zone (generator output).

  According to the gas turbine load control device of the third aspect of the invention, the first bias setting means gradually increases the positive bias value from zero at a predetermined increase rate when the load setting means starts increasing the load setting value. Increase until a predetermined value is reached, and when the load setting means finishes increasing the load set value, decrease it from a predetermined value to zero gradually at a predetermined decrease rate, and the second bias setting In the means, the positive bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when the load setting means starts to decrease the load setting means, and the load setting value is increased in the load setting means. When ending the decrease, it is characterized by gradually decreasing from a predetermined value until it becomes zero at a predetermined decreasing rate, so compared to the case where the plus side bias value and the minus side bias value are changed stepwise, Yo Thus enabling stable load control.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a gas turbine load control device according to an embodiment of the present invention, FIG. 2 is a functional explanatory diagram of an analog memory provided in the gas turbine load control device, and FIGS. FIG. 5 and FIG. 6 are functional explanatory diagrams of the rate-equipped switching device provided in the gas turbine load control device.

  FIG. 7 is an explanatory diagram individually showing changes in LDSET, target output, generator output (actual output), etc. with respect to an increase in required load set value when the gas turbine load control device is applied, and FIG. FIG. 9 is an explanatory diagram collectively showing changes in LDSET, target output and generator output (actual output) with respect to an increase in required load set value when a turbine load control device is applied. FIG. 9 is a case where the gas turbine load control device is applied. FIG. 10 is an explanatory diagram individually showing changes in LDSET, target output, generator output (actual output), and the like with respect to a decrease in required load set value. FIG. 10 shows a decrease in required load set value when the gas turbine load control device is applied. It is explanatory drawing which shows collectively the change of LDSET with respect to, target output, and generator output (actual output).

  As shown in FIG. 1, the gas turbine power generation facility has a configuration in which a rotating shaft 14 of a generator 23 is connected to a rotating shaft 22 of a gas turbine 21. Although detailed illustration is omitted, the gas turbine 21 includes a gas turbine main body, a compressor, and a combustor. When the gas turbine 21 is activated, the generator 23 is rotationally driven by the gas turbine 21 to generate power. The generated power is transmitted from the generator 23 to the power system via a circuit breaker, a transformer, etc. (not shown). The value of the generated power (active power) at this time is converted by the MW converter 25 which is an active wattmeter. It is measured. The measured value (actual output) of the MW converter 25 is fed back to the gas turbine load control device 30.

  Further, a fuel control valve 26 is connected to the combustor of the gas turbine 21 as a gas turbine fuel flow control means, and a gas turbine such as gas or liquid sent from a fuel supply facility such as a fuel tank (not shown). The fuel is supplied to the combustor after the flow rate is controlled by the fuel control valve 26. Then, the gas turbine load control device 30 performs opening / closing control of the fuel control valve 26 (control of the supplied fuel amount).

  The gas turbine load control device 30 includes deviation calculators (subtractors) 31 and 44, high / low monitors (comparators) 32 and 33, an analog memory 34, function generators 35 and 36, rate-changers 37 and 38, a signal generator. 39, 40, an adder 41, a subtractor 42, and a PI controller 44. Deviation calculator 31, high / low monitors 32 and 33 and analog memory 34 function as load setting means, function generator 35, signal generator 39 and rate-equipped switching device 37 function as first bias setting means, and function generation 36, the signal generator 40 and the rate-equipped switch 38 function as second bias setting means, the adder 41 and subtractor 42 function as target output setting means, and the deviation calculator 43 functions as output deviation calculating means. The PI controller 44 functions as a proportional / integral control means. In addition, although each function of these gas turbine load control apparatuses 30 is comprised with software, and is performed with a computer, it is not limited to this, You may comprise with hardware.

  The deviation calculator 31 is a deviation between a required load setting value (command) sent from a central power supply center (upper computer) (not shown) as required load setting means and LDSET (load setting value) as an output of the analog memory 34. (Load setting deviation = Requested load setting value−LDSET) is calculated. The required load setting means is not necessarily limited to the central power supply center (higher computer), but may be other ones. For example, a load setting device provided in a gas turbine power generation facility may be used.

  When the required load set value increases, the high / low monitor 32 determines whether or not LDSET has increased to reach the required load set value. Specifically, the high / low monitor 32 determines whether or not the load setting deviation is 0.1 MW or more (load setting deviation ≧ 0.1 MW), and if it is determined that the load setting deviation is 0.1 MW or more, An LDSET increase command is output to the analog memory 34, and a plus side bias switching command SW1 (ON) is output to the rate changer 37. That is, the LDSET increase command is turned ON when the load setting deviation is 0.1 MW or more, and turned OFF when the load setting deviation is smaller than 0.1 MW. The plus side bias switching command SW1 is turned on when the load setting deviation is 0.1 MW or more, and turned off when the load setting deviation is smaller than 0.1 MW. Although the determination value is 0.1 MW here, the determination value is not limited to this, and a value smaller or larger than 0.1 MW can be set as appropriate.

  When the required load set value decreases, the high / low monitor 33 determines whether or not LDSET has decreased to reach the required load set value. Specifically, the high / low monitor 33 determines whether or not the load setting deviation is −0.1 MW or less (load setting deviation ≦ −0.1 MW), and determines that the load setting deviation is −0.1 MW or less. In this case, an LDSET decrease command is output to the analog memory 34, and a minus side bias switching command SW2 (ON) is output to the rate switching device 37. That is, the LDSET reduction command is turned on when the load setting deviation is −0.1 MW or less, and is turned off when the load setting deviation is larger than −0.1 MW. Further, the minus side bias switching command SW2 is turned ON when the load setting deviation becomes −0.1 MW or less, and turned OFF when the load setting deviation becomes larger than −0.1 MW. Here, the determination value is set to −0.1 MW, but the determination value is not limited to this, and a value smaller or larger than −0.1 MW can be set as appropriate.

  In the analog memory 34, when an LDSET increase command is input from the high / low monitor 32 as illustrated in FIG. 2 (when the LDSET increase command is turned ON), an increase in LDSET is started and the LDSET increase command is continuously input ( While the LDSET increase command is ON), LDSET is gradually increased at a predetermined increase rate (for example, 10 MW / min), and when the LDSET increase command is not input from the high / low monitor 12 (when the LDSET increase command is turned OFF), LDSET Stop increasing. Further, in the analog memory 34, when an LDSET decrease command is input from the high / low monitor 33 as illustrated in FIG. 2 (when the LDSET decrease command is turned ON), the decrease of the LDSET is started and the LDSET decrease command is continuously input. During the interval (while the LDSET decrease command is ON), the LDSET is gradually decreased at a predetermined decrease rate, and when the LDSET decrease command is not input from the high / low monitor 33 (when the LDSET decrease command is turned OFF), the decrease in LDSET is stopped. To do.

  As described above, gradually increasing or decreasing the LDSET using the analog memory 34 in this manner causes the LDSET to change at an allowable change rate of the gas turbine 21 even if the required load set value changes abruptly. Because. If the LDSET is also changed abruptly in response to a sudden change in the required load set value, the output of the gas turbine 21 may change abruptly, resulting in damage to the gas turbine 21 and the like. Note that the increase rate and decrease rate of LDSET in the analog memory 34 may be the same or different, and an optimal value may be set as appropriate for each gas turbine power generation facility.

  Then, the LDSET set in the analog memory 34 is not directly used as the target output of the generator 23, but is added with a bias as a target output of the generator 23. Therefore, the adder 41 and the function generator 35 are used. And the function generator 36, respectively.

  In the function generator 35, as illustrated in FIG. 3, a predetermined value that increases in accordance with an increase in LDSET output from the analog memory 34 is set as a positive bias value. In the example of FIG. 3, the function generator 35 increases the LDSET from 1 MW to 2 MW in response to the increase in LDSET from 0 MW to the maximum load setting value (240 MW in the illustrated example). That is, the positive side bias value is not a constant value but a function of LDSET. The reason why the plus side bias value is used as a function of LDSET is that the appropriate plus side bias value varies depending on the gas turbine load zone (generator output). In the signal generator 39, zero (S = 0) is set.

  In the function generator 36, as illustrated in FIG. 4, a predetermined value that decreases in accordance with a decrease in LDSET output from the analog memory 34 is set as a negative side bias value. In the example of FIG. 4, the function generator 36 reduces the LDSET from 2 MW to 1 MW in response to the decrease in the LDSET from the maximum load setting value (240 MW in the illustrated example) to 0 MW. That is, the minus side bias value is not a constant value but a function of LDSET. The reason why the negative side bias value is used as a function of LDSET in this manner is that the appropriate negative side bias value varies depending on the gas turbine load zone (generator output). In the signal generator 40, zero (S = 0) is set.

  Of course, the positive side bias value and the negative side bias value are not limited to 1 to 2 MW, but the degree of improvement in the followability of the generator output with respect to the change in the required load setting value (how fast it should follow) and the load In consideration of control stability, the optimum value for each gas turbine power generation facility may be set as appropriate by calculation or trial operation. Further, the plus side bias value and the minus side bias value are the same values in the examples shown in FIGS. 3 and 4 and linearly increase / decrease in accordance with the increase / decrease of LDSET, but the present invention is not limited to this. There may be different values, and the method of increasing / decreasing according to the increase / decrease of LDSET may not be linear.

  In the rate switching device 37, the output of the function generator 35 or the output of the signal generator 39 is selected as the output to the adder 41. That is, when the plus side bias switching command SW1 input from the high / low monitor 32 is ON, the rate switching unit 37 switches to the function generator 35 side and outputs the output of the function generator 35 to the adder 41. When the plus side bias switching command SW1 is OFF, the signal generator 39 is switched to the output side, and the output of the signal generator 39 is output to the adder 41.

  Further, since the rate switch 37 is rate-added, the positive side bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when starting to increase LDSET in the analog memory 34, In addition, when the increase in LDSET is finished in the analog memory 34, the analog memory 34 is decreased from the predetermined value to zero gradually at a predetermined decrease rate.

  Specifically, as illustrated in FIG. 5, when the required load set value increases and the high / low monitor 32 outputs an LDSET increase command (turns ON), the analog memory 34 increases the LDSET. When starting, since the plus side bias switching command SW1 output from the high / low monitor 32 simultaneously with the LDSET increase command is also turned ON, the rate switch 37 switches the output from the signal generator 39 to the output of the adder 41 ( Switching from SG (S = 0) in the figure to the output of the function generator 35 (FX in the figure), but at this time, the positive side bias value is not increased stepwise but at a predetermined rate of increase. Gradually increase from zero (output value of the signal generator 39) to a predetermined value (output value of the function generator 35). In addition, when the LDSET reaches the required load setting value and the LDSET increase command from the high / low monitor 32 is turned OFF, when the increase of LDSET is finished in the analog memory 34, the high / low monitor 32 is simultaneously with the LDSET increase command. Since the plus-side bias switching command SW1 output from is also turned OFF, the rate-switching device 37 changes the output to the adder 41 from the output of the function generator 35 (FX in the figure) to the output of the signal generator 39 (see FIG. However, the positive bias value is not decreased stepwise, but gradually from a predetermined value (output value of the function generator 35) at a predetermined decrease rate. Decrease until zero (output value of signal generator 39). Note that the specific rate (increase rate and decrease rate) of the switch 37 with rate is appropriately set by calculation, trial operation, etc. in consideration of the stability of load control and the like. do it.

  The rate switching unit 38 switches whether the output of the function generator 36 or the output of the signal generator 40 is selected as the output to the subtracter 42. That is, when the negative side bias switching command SW2 input from the high / low monitor 33 is ON, the rate switching unit 38 switches to the function generator 36 side and outputs the output of the function generator 36 to the subtractor 42. When the minus side bias switching command SW2 is OFF, switching to the signal generator 40 side is performed, and the output of the signal generator 40 is output to the subtractor 42.

  Further, since the rate switch 38 is rate-added, the negative bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when starting the decrease of LDSET in the analog memory 34, When the analog memory 34 finishes reducing the LDSET, the analog memory 34 decreases the predetermined value from the predetermined value to zero.

  Specifically, as illustrated in FIG. 6, when the required load set value decreases and the LDSET decrease command is output from the high / low monitor 33 (turns ON), the analog memory 34 reduces the LDSET. When starting, since the minus side bias switching command SW2 output from the high / low monitor 33 is also turned ON simultaneously with the LDSET decrease command, the rate-change switch 38 outputs the output to the subtractor 42 (the output of the signal generator 40 ( The SG (S = 0) in the figure is switched to the output of the function generator 36 (FX in the figure). At this time, the negative bias value is not increased stepwise but at a predetermined rate of increase. Gradually increase from zero (output value of the signal generator 40) to a predetermined value (output value of the function generator 36). When the LDSET reaches the required load setting value and the LDSET reduction command from the high / low monitor 33 is turned OFF, when the analog memory 34 finishes reducing the LDSET, the high / low monitor 33 is simultaneously with the LDSET reduction command. Since the minus side bias switching command SW2 output from is also turned off, the rate switching unit 38 changes the output to the subtractor 42 from the output of the function generator 36 (FX in the figure) to the output of the signal generator 40 (in the figure). However, the negative bias value is not decreased stepwise, but gradually from a predetermined value (output value of the function generator 36) at a predetermined decrease rate. Decrease until zero (output value of signal generator 40). Note that the specific rate (increase rate and decrease rate) of the rate switching unit 38 is also set appropriately by calculation, trial operation, etc. in consideration of the stability of load control and the like. do it.

  The adder 41 sets the target output of the generator 23 by adding the positive side bias value output from the rate-equipped switch 37 to the LDSET output from the analog memory 34. In the subtracter 43, the target output of the generator 23 is set by subtracting the negative side bias value output from the rate switch 38 from the output value from the adder 41, that is, LDSET output from the analog memory 34. To do. It should be noted that the plus side bias switching command SW1 of the high / low monitor 32 and the minus side bias switching command SW2 of the high / low monitor 33 are not simultaneously turned on, and the switching to the function generator 35 side in the rate switching device 37 is performed. And the switching to the function generator 36 side in the rate switching unit 38 are not performed at the same time, so the adder 41 adds the output (plus bias value) of the function generator 35 to the LDSET. And the subtracter 42 does not subtract the output (minus bias value) of the function generator 36 at the same time.

  In the deviation calculator 43, the target output of the generator 23 set by the adder 41 or the subtracter 42 (LDSET plus a bias), the generator output (active power) measured by the MW converter 25, and Deviation (output deviation = target output-generator output) is calculated.

  The PI controller 44 controls the opening of the fuel control valve 26 by performing proportional / integral calculation based on the output deviation calculated by the deviation calculator 43. That is, if the target output is larger than the generator output (actual output), the gas turbine output is increased by increasing the opening of the fuel control valve 26 and increasing the amount of fuel supplied to the gas turbine 21 (combustor). To increase the generator output (actual output) (make the generator output coincide with the target output). Further, if the target output is smaller than the generator output (actual output), the gas turbine output is reduced by reducing the amount of fuel supplied to the gas turbine 1 (combustor) by reducing the opening of the fuel control valve 26. To reduce the generator output (actual output) (make the generator output coincide with the target output). In the deviation calculator 44, K is a proportional gain, s is a Laplace operator, T is a time constant (integral time constant) of proportional / integral control, and 1 / T is an integral gain.

  Specifically, as illustrated in FIGS. 7 and 8, for example, the required load set value, the LDSET, the target output, and the generator output (actual output) coincide with each other until time T1. When the required load set value increases stepwise (in the example shown from 100 MW to 200 MW) in response to a command from the center, the deviation between the required load set value calculated by the deviation calculator 31 and LDSET is 0.1 MW or more. Therefore, the LDSET increase command is output from the high / low monitor 32 to the analog memory 34 (the LDSET increase command is turned ON). As a result, the analog memory 34 causes LDSET to reach the required load setting value (200 MW) at time T3 from time T1 (until the load setting deviation becomes smaller than 0.1 MW and the LDSET increase command is turned OFF). It gradually increases at a predetermined rate of increase.

  In this case, since the positive side bias switching command SW1 output from the high / low monitor 32 is turned on at time T1, the rate switching unit 37 sends the output to the adder 41 from the output of the signal generator 39 to the function generator 35. Switch to output. As a result, the positive side bias value output from the rate changer 37 gradually increases from zero (the output value of the signal generator 39) to a predetermined value (the output value of the function generator 35) at a predetermined increase rate ( Increases until time T2). Thereafter, when the plus-side bias switching command SW1 is turned OFF at time T3, the rate switch 37 switches the output to the adder 41 from the output of the function generator 35 to the output of the signal generator 39. As a result, the positive side bias value output from the rate switching device 37 gradually decreases at a predetermined decrease rate from a predetermined value (output value of the function generator 35) to zero (output value of the signal generator 39) ( Decrease until time T4).

  Then, the plus side bias value at this time is added to LDSET by the adder 41, whereby the target output of the generator 23 is set. Subsequently, an output deviation between the target output and the generator output (active power) is calculated by the deviation calculator 43, and a proportional / integral calculation is performed by the PI controller 44 based on the output deviation. Based on the calculation result, the fuel control valve 26 operates (the valve opening of the fuel control valve 26 increases). As a result, the amount of fuel supplied to the gas turbine 21 increases and the gas turbine output increases, so that the generator output (active power) increases, and finally the generator output (active power) is set to the target output ( The required load setting value) can be matched.

  Further, as illustrated in FIG. 9 and FIG. 10, the required load set value, LDSET, target output, and generator output (actual output) coincide with each other until time T1, and at time T1, according to a command from the central power feeding center. When the required load set value decreases stepwise (in the example shown, from 200 MW to 100 MW), the deviation between the required load set value calculated by the deviation calculator 31 and LDSET is −0.1 MW or less. / The LDSET reduction command is output from the low monitor 33 to the analog memory 34 (the LDSET reduction command is turned ON). As a result, the analog memory 34 causes LDSET to reach the required load setting value (200 MW) at time T3 from time T1 (until the load setting deviation becomes larger than −0.1 MW and the LDSET reduction command is turned OFF). , Gradually decrease at a predetermined decrease rate.

  In this case, since the minus side bias switching command SW2 output from the high / low monitor 33 is turned on at the time T1, the rate switch 38 outputs the output to the subtractor 42 from the output of the signal generator 40 to the function generator 36. Switch to output. As a result, the negative side bias value output from the rate changer 38 gradually increases at a predetermined increase rate from zero (the output value of the signal generator 40) to a predetermined value (the output value of the function generator 36) ( Increases until time T2). Thereafter, when the minus-side bias switching command SW2 is turned OFF at time T3, the rate switch 38 switches the output to the subtractor 42 from the output of the function generator 36 to the output of the signal generator 40. As a result, the negative side bias value output from the rate-equipped switch 38 gradually decreases at a predetermined decrease rate from a predetermined value (output value of the function generator 36) to zero (output value of the signal generator 40) ( Decrease until time T4).

  Then, the minus side bias value at this time is subtracted from the LDSET by the subtractor 42, whereby the target output of the generator 23 is set. Subsequently, an output deviation between the target output and the generator output (active power) is calculated by the deviation calculator 43, and a proportional / integral calculation is performed by the PI controller 44 based on the output deviation. Based on the calculation result, the fuel control valve 26 operates (the valve opening of the fuel control valve 26 decreases). As a result, the amount of fuel supplied to the gas turbine 21 decreases and the gas turbine output decreases, so that the generator output (active power) decreases, and finally the generator output (active power) is set to the target output ( The required load setting value) can be matched.

  As described above, according to the gas turbine load control device 30 of the present embodiment, the target output setting means (adder 41, subtractor 42) does not directly set LDSET as the target output of the generator 23. When the load setting value is gradually increased by the load setting means (deviation calculator 31, high / low monitors 32, 33, analog memory 34) in response to an increase in the required load setting value input from the required load setting means. When the target output of the generator 23 is set by adding the plus side bias value to LDSET and the load setting value is gradually decreased by the load setting means in accordance with the decrease in the required load setting value, Since the target output of the generator 23 is set by subtracting the negative side bias value, for example, the gas turbine 21 is stabilized against power factor fluctuations in the power system. Also the time constant T of the proportional-integral control as is possible to rolling set longer, it is possible with an increase or decrease in the required load set value, to increase the follow-up of the generator output.

  For example, when FIG. 8 is compared with FIG. 12, compared with the conventional gas turbine load control apparatus that uses LDSET as a target output as it is (FIG. 12), this book sets the target output by adding a positive bias value to LDSET. In the case of the gas turbine load control device 30 according to the embodiment (FIG. 8), it can be seen that the generator output follows the change in the required load set value more quickly by adding the positive side bias value. .

  Further, according to the gas turbine load control device 30 of the present embodiment, the first bias setting means (the function generator 35, the signal generator 39, and the rate-equipped switching device 37) sets the plus side bias value to the LDSET function. In the second bias setting means (the function generator 36, the signal generator 40, and the rate-equipped switch 38), in order to make the negative side bias value a function of LDSET, the positive side bias value and the negative side bias value are It can be set to a more appropriate value according to the gas turbine load zone (generator output).

  Further, according to the gas turbine load control device 30 of the present embodiment, the first bias setting means (the function generator 35, the signal generator 39, and the rate-equipped switch 37) sets the plus side bias value to the load setting means. (Deviation calculator 31, high / low monitors 32, 33, analog memory 34) When increasing LDSET is started, gradually increase from zero to a predetermined value at a predetermined increase rate, and load setting means When the increase in LDSET is completed, the second set value is decreased from a predetermined value until it gradually becomes zero at a predetermined decrease rate, and second bias setting means (function generator 36, signal generator 40, rate-equipped switch 38) ) Increase the positive bias value gradually from zero to a predetermined value at a predetermined increase rate when the load setting means starts to decrease the load setting value. In addition, when the load setting means finishes reducing the load set value, the load setting means gradually decreases from the predetermined value to zero with a predetermined decrease rate. Compared with the case where the value is changed stepwise, more stable load control is possible.

  The present invention relates to a gas turbine load control device for controlling the amount of fuel supplied to a gas turbine so that the gas turbine output (generator output) becomes a target output, and a required load setting means such as a central power supply center. This is useful when applied to improve the follow-up property (responsiveness) of the generator output with respect to the change in the required load setting value required (input) from the above.

It is a block diagram which shows the structure of the gas turbine load control apparatus which concerns on the example of embodiment of this invention. It is function explanatory drawing of the analog memory with which the said gas turbine load control apparatus was equipped. It is function explanatory drawing of the function generator with which the said gas turbine load control apparatus was equipped. It is function explanatory drawing of the function generator with which the said gas turbine load control apparatus was equipped. It is function explanatory drawing of the switch with a rate with which the said gas turbine load control apparatus was equipped. It is function explanatory drawing of the switch with a rate with which the said gas turbine load control apparatus was equipped. It is explanatory drawing which shows the change of LDSET with respect to the increase in a required load setting value at the time of applying the said gas turbine load control apparatus, a target output, a generator output (actual output), etc. separately. It is explanatory drawing which shows collectively the change of LDSET with respect to the increase in a required load setting value at the time of applying the said gas turbine load control apparatus, a target output, and a generator output (actual output). It is explanatory drawing which shows the change of LDSET with respect to the reduction | decrease of the required load setting value at the time of applying the said gas turbine load control apparatus, a target output, a generator output (actual output), etc. separately. It is explanatory drawing which shows collectively the change of LDSET with respect to the reduction | decrease of the required load setting value at the time of applying the said gas turbine load control apparatus, a target output, and a generator output (actual output). It is a block diagram which shows the structure of the conventional gas turbine load control apparatus. It is explanatory drawing which shows the change of LDSET (target output) and a generator output (actual output) with respect to the increase in a required load setting value at the time of applying the said gas turbine load control apparatus.

Explanation of symbols

21 Gas Turbine 22 Rotating Shaft 23 Generator 24 Rotating Shaft 25 MW Converter 26 Fuel Control Valve 30 Gas Turbine Load Control Device 31 Deviation Calculator (Subtractor)
32, 33 High / Low monitor 34 Analog memory 35, 36 Function generator 37, 38 Switch with rate 39, 40 Signal generator 41 Adder 42 Subtractor 43 Deviation calculator (subtractor)
44 PI controller

Claims (3)

When the required load set value increases, the load set value is gradually increased at a predetermined increase rate until the required load set value is reached, and when the required load set value decreases, the load set value is changed to the required load set value. Load setting means for gradually decreasing at a predetermined decrease rate until reaching
First bias setting means for setting a positive bias value as a bias value for the load setting value;
Second bias setting means for setting a negative side bias value as a bias value for the load setting value;
When the load setting value is gradually increased by the load setting means in response to the increase in the required load setting value, the target output of the generator is obtained by adding the plus side bias value to the load setting value. When the load setting value is gradually decreased by the load setting means in accordance with a decrease in the required load setting value, the target output is obtained by subtracting the negative side bias value from the load setting value. Target output setting means for setting
Output deviation calculating means for calculating an output deviation between the target output and the generator output measured by the generator output measuring means;
A gas turbine load comprising: proportional / integral control means for controlling a flow rate control means for a fuel of a gas turbine that rotationally drives the generator by performing proportional / integral calculation based on the output deviation Control device. In the gas turbine load control device according to claim 1,
In the first bias setting means, the positive side bias value is a function of the load setting value,
In the second bias setting means, the minus bias value is a function of the load setting value. In the gas turbine load control device according to claim 1 or 2,
In the first bias setting means, the positive bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when the load setting means starts to increase the load setting value, And, when the load setting means ends the increase of the load set value, the load set means decreases the predetermined value from the predetermined value until it gradually becomes zero,
In the second bias setting means, the positive bias value is gradually increased from zero to a predetermined value at a predetermined increase rate when the load setting means starts to decrease the load setting value, The gas turbine load control device is characterized in that when the load setting means finishes decreasing the load set value, the load set means decreases the load set value gradually from the predetermined value to zero at a predetermined decrease rate.

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